What is 'Force Majeure' in ICC contracts, and why does ICC-PCB dispute matter amid India match boycott in T20 World Cup?

What is 'Force Majeure' in ICC contracts, and why does ICC-PCB dispute matter amid India match boycott in T20 World Cup?
The term ‘Force Majeure’ has come into sharp focus following the recent controversy surrounding the boycott of a high-profile ICC T20 World Cup fixture.